Process for producing butadiene



Patented Jan. 28, 1941 UNITED STATES.

2,229,652 7 PROCESS ron rnonuomc. BUTADIENE Paul Halbig, Munich,

Norbert Platzer, Burghausen, and Ali'red Treibs, Munich, Germany, assignors to Consortium fiir Elektrochemische Industrie G. m. b. 11., Munich, Germany, a corporation of Germany No Drawing. Application January 13, 1939, Se-

rial No. 250,736.

4 Claims.

We have found that 1,3-butylene-g1yco1 and its 5 ether,

in liquid phase may be dissociated to butadiene with good results at low temperatures.

In order to obtain the best yields it is necessary to efiect the dissociation in the presence of a substantial amount of water and to remove the butadiene from the reaction system immediately upon its formation. Suitable catalysts are dehydration media such as sulphuric acid, its acid salts, sulfo-acids, phosphoric acid, perchloric acid, etc.', and mixtures of these compounds. The reaction temperature depends on the type of 2 catalyst and its concentration. The reaction may be performed at temperatures around 200 C. with 1% sulphuric acid. With stronger sulphuric acid the reaction begins around 140 C.

The reaction is explained in the following ex- 25 ample.

Example 80 parts 1,3-butylene- 1ycol are dissolved in parts water. This solution is added at the rate of about 800 parts per hour to 2000 parts of 1% sulphuric acid which are boiling at about 200. C.

In Germany February 9, 1938 or mixtures of said ether and the glycol, in aqueous solution.

The reaction in the presence of potassium bisulphate, toluol-sulfo acid, aluminium sulphate, alum and other catalysts acting as mineral acids may be performed in a similar manner.

The invention claimed is:

1. Process for producing butadiene which comprises heating a compound having the general formula CHa-CHOH-CHz-CHaOR in which R. is a member selected from the group consisting of hydrogen, CH.-zCH2CHOH-CH 1 and mixtures of the same, and an aqueous solution of a dehydration catalyst containing water in a quantity greater than the quantity of said compound to a temperature higher than 100 C. under pressure, and removing the butadiene from the reaction zone as soon as it is formed.

2. Process for producing butadiene which comprises heating 1,3-butylene-glycol, and an aqueous solution of a dehydration catalyst containing water in, a quantity greater than the quantity of said compound to a temperature higher than 100 C. under pressure, and removing the butadiene from the reaction zone as soon as it is formed.

3. Process for producing butadiene which comprises heating in a pressure vessel. The dissociation of the lasts a very long time, since S02 and other sulphur-containing dissociation products are not generated in appreciable amounts. The yield of butadiene is about theory.

45 The same result is obtained by using the ether of the formula cm-cHoH-em-cmand an aqueous solution of a dehydration catalyst containing water in a quantity greater than the quantity of said compound to a temperature higher than C. under pressure, and removing the butadiene from the reaction zone as soon as it is formed.

4. Process for producing butadiene whichcomprises heating 1,3-butylene-glycol and an aqueous solution of sulfuric acid containing water in a quantity greater than the quantity of 1,3-butylene-glycol to a temperature of about C. to 200 C. under pressure, and removing the hutadiene from the reaction zone as soon as it is formed.

PAUL HALBIG. NORBERT PLATZER. ALFRED TREIBS. 

